The brushhead/handle interface includes a brushhead assembly (20) which has a brush member (26) for cleaning teeth. A driveshaft (14) extends from a handle portion (12) of the toothbrush (10), which is driven in an oscillating manner through a selected rotational angle. The driveshaft includes one or more contact regions (49). The coupling member includes an interface portion or portions (46) which are forced against the contact regions of the driveshaft by a single spring member when the driveshaft is inserted into the coupling member. The single spring (34) exerts a sufficient force on the interface portions of the coupling member against the contact regions of the driveshaft to produce both a reliable torque transfer between the driveshaft and the brushhead assembly and to maintain axial retention of the brushhead assembly on the driveshaft during operation of the toothbrush.